Hi all,I probably found a bug when calculating eigenvectors of a symmetric matrix with DSYEV + ESSL on a Power6 IBM cluster.The bug appears only when the matrix is diagonalized by using the upper half, and when the leading dimension n>200 approx.

Hi Julie,sorry, maybe I was unclear.I tested with netlib lapack-3.2.1 installed with XL compiler.When I tried with intel mkl everything was fine. So I would think that this bug is related to the interface of lapack with ESSL.

Fabio,Could you try with the latest LAPACK release LAPACK 3.3.0, calling the LAPACK routine without the interface?LAPACK 3.3.0 is available at http://netlib.org/lapack/#_softwareESSL and MKL are vendors libraries. If you do not have the bug with LAPACK 3.3.0, you should report the problem directly to the ESSL guys.Julie

Julie,as far as i know, lapack cannot be linked without including ESSL on power ibm systems. I know this is a proprietary software but I was wondering if the bug was pertinent to ESSL or to lapack libraries.Anyway, the same problem persists also in the latest release.

I don't think so. To run LAPACK on a machine, you just need a Fortran compiler.Just download the netlib LAPACK, compile and generate the library.You have to add the -qfixed flag. Best is to put it on the FORTRAN and LOADER variables in the make.inc:

After, your program has to be changed to follow the LAPACK interface.Regarding the BLAS library to use, it would be better to use the Reference BLAS than ESSL.I currently do not have a IBM machine to test your program.